| 摘要 |
PURPOSE:To multiply a carrier frequency by n times by setting the time difference of an interrupt signal to a microprocessor of n pieces of pulse forming circuits to 1/n or larger of an intrinsic carrier period T, and setting the ON period of a PWM pulse pattern to 1/n or lower of T. CONSTITUTION:The output of an oscillator 7 is divided in frequency by a frequency divider 8, input to an n-bit (n=2) shift register 11, two timing signals D1, D2 are output from generators 13, 13, and interrupted and input to a microprocessor 1. The time difference of signals D1, D2 is set to 1/2 or larger of the intrinsic carrier period T. The microprocessor reads out the time information (time to rising or falling) of a pulse train from a memory 2 by interrupt signals D1, D2, is latched by a latch 3, FF6 is set at S or reset at R by counting up counters 4, 5. Both FFs 6 are alternately output, a signal J from an OR circuit 10 is output, and a PWM is turned ON during 1/n or lower of the carrier period T. Thus, the carrier frequency is multiplied by n. |
